Hydraulic brake



Jan. 1, 1935. H Q RHODES 1,986,763

HYDRAULI C BRAKE Filed March 9. 195i III/lll 4 AT1-0R NITJ$ PatentedJana 1, 1935 UNITED ySTATES f PATENT oFFlcE signor -of one-half tohnrst, Ohio Victor Fr Germ, Lynd- Appummfxuc'h 9, 1931, sei-m No, szLusr1 claims. (ci. en -54.5)

' 'Ihis invention relates to hydraulic brakes, more particularly adaptedforV `automobiles, and an object of the invention is to provide new andimproved devices of this type.

In the drawing accompanying this specification and forming a part ofthis application, I have shown for purposes of illustration, one formwhich my invention may assume, and in this drawing: f

Figure 1 is a fragmentary side elevational view of an embodiment of theinvention,

Figure 2 is an enlarged horizontal sectional view correspondingsubstantially tothe'line 2-2 Figure 3 is a vertical sectional viewcorresponding substantiallyto the line 3--3 of Figure 2,.

Figure 4 is a vertical sectional view corresponding substantially to theline 4-.4 of Figure 2,

while l i sectional view of the wheel brake cylinder and pistons.

The embodiment of the invention herein disclosed comprises a mastercylinder 10, havingadjacent one end 11 an interior partition 12 forminga chamber 13, communicating `with the cylinder 10 through an opening 14,surrounded by a rib 15, providing a seat for one end of a springl, theopposite end of which bearsupon a piston 17. slidably disposed inthe'cylinder 10. The piston 17 at its outer side is provided with a recess18 adapted for the reception of. the inner end of a piston rod 19,connected to a brake pedal 20, and attached'to the cylinder 10 and the,piston rod -19 is a collapsible sealing member 21. Above the mastercylinder 10 and integral thereof isa store age reservoir 22, having aremovable cover 23, and

communicating by means of a port 24 with the cylinder 10.

d6 Preferably cast with one side ofthe masterl cylinder 10 isa brakeactuating device', indicated generally by the reference character y25,and in the embodiment shown comprising two cylinders 26 and 27 arrangedin tandem, communicating. with the cylinder 1 0 `through the port 28,and communicating with each other through the port One pair of ends 30of the cylinders 26 and 27 are closed by a common plate 31, secured inposi- Y tion by screws 32, with suitable interposed packing 33, and thevplate 31 is provided with an opening-34 arranged axially in line withthe cylinder 26 and having an inwardly extending'boss 35therearoimdthrough-whichextendsaiitting 36llhnvingaiiangearbeu'insssainsttheendoi.

Figure 5 is an enlarged fragmentary verticall the boss 35, and outwardlyof the plate 31 threaded for the reception of a securing nut 38, withinterposed packing 39, the fitting 38 forming part of a flexible conduit40 extending to one of the brake devices 41 associated with one 4of thefront 5 wheels of `a vehicle, such as shown in Figures 1 and 5 of thedrawing, and which comprises brake shoes 42 normally held disengaged bya spring 43, adapted to be engaged by a pair of opposed pistons 44,carried in a cylinder 45, and operatively 10 disposed to bear againstthe ends of the brake shoes 42 when iluid'isv admittedto the lcylinder45` through the port 46 from the conduit 40. A vsecond conduit 47communicates axially with the adjacent end of the cylinder 27 throughthe plate 15 l 31 in the same manner as describedin connec.-

tion with the conduit 40, the conduit 47 leading to a brake devicesimilar to 41 heretofore described, such device however being associatedwith one'of the rear wheels ofthe vehicle. The n oppodte pair of en ds48 of the cylinders 26 and 27 likewise are closed by a common plate 49,having a conduit 50 communicating with the cylinder 26 leading to theother front wheel brake device of 'the vehicle, and a conduit 51communicating 25 with the cylinder 27 and leading to the other rearwheel brake device of the vehicle, the conduits 50 and 51, and the brakedevices adjacent the wheels being of the character heretofore describedin detail. t Y Y Slidably mounted in the cylinder'26 is a pair ofpistons 52 and 53, each comprising a disk 54 to .the inner surface ofwhich is secured a cup-shaped washer 55 held by a plate 56 secured by a'screw .57, and the opposite f'ace of the disk-54 has an 35 oppositelywasher 58 secured thereto, held in position by a plate 59, providedwitha boss 60, and secured by a screw 61. Acoiled expension spring 62 isinterposed between the 'plate 59and'the plate 31 and surrounds thebosses 40 35 and 60, and normally urges thepiston-53 towardthe piston52, and since both piston constructions are the same, thepistons 52 and53 are normally urgedj-j toward each other, but arelimitedinthismovementbyapairofspaoedresil- 45 ient stop strips 61*supported in notches '62 formed in the interior wall of the cylinder 26,andthe port 28 isso-located as to aord communication with the cylinder26 only between the pawns 52 and sa. 5

Auxiliary reservoirsw63 are'provided for the cylinder 26, and eachoomprkes an integral .ienlargement having a chamber.64. one reservoirhavinga duct 65 communicating with the cylin- (ii' 36 mithepiston 52nndtheadjaht 67 communicating by a port 68, controlled by af plate 49and the other having a duct 66 communicating with the cylinder 26between the piston 53 and the plate 31, the ducts 65 and 66 being P051-tioned to be open when the pistons 52 and 53 are retracted, but to beclosed by said pistons immediately Pressure is placed thereon.

The cylinder 26 is also provided with a by-pass needle valve 69, withthe space betwen the pistons 52 and 53, communicating also by a port 10,controlled by a needle valve 71, with the space between the piston 53and the plate 31, and additionally communicating by a port 72,controlled by a needle valve 73, with the space between the piston 52and the plate 49, and the cylinder 27 is provided with a similararrangement.

The pistons 74 and 75 inthe cylinder 27 and associated constructionshown, are identical to those described in connection with the cylinder26, and the cylinder 27 and pistons 74 and 75 operate in tandem with thecylinder 26 and pistons 52 and 53, communication being provided throughthe port 29, as will be understood.

In preparing the system for use the needle valves 69, 71, and 73 areoperated to open the ports 68, 70, and 72, and iuid is introduced intothe system through the reservoir 22, ilowing thence through the port 24,into the master cylinder 10, thence through the port 28. through theport 29, through the by-pass 67 of each of the cylinders 26 and27,'passing thence into the ends o! the cylinders 26 and 27, thencethrough the conduits 40, 47, 50, and 51. to the brakecylinders 45,sufficient uid being introduced to entirely iill the system, and thereservoirs 63 and 22 as well. When iilling has been completed the needlevalves 69, 71, and 73 are screwed home to close the ports 68, 70, and72, thereby separating the iluid in the System into segregated bodies,that contained within the reservoir 22, the master cylinder 10, and thespaces between the pistons 52 and 53 of the cylinder 26 and pistons 74and 75 of the cylinder 27, on the one hand, and those contained betweenthe outer faces lof the pistons 52 and 53 of the cylinder 26, and thepistons 74 and 75 of the cylinder 27, and adjacent end walls ci' saidcylinders, and in the conduits 40, 47, 50, and 51, and in the cylinders45, on the other hand, so that the ilrst body of iluid has nocommunication with the individual bodies associated with each brakedevice.

. Normally the piston 17 isheld retractedby the spring 16 and thepistons52, 53, 74, and'75-are likewise held retracted by the springsv62. and the brake shoes are held retracted'by springs43; and normallythe iluid in the system isrfree from pressure. When thepedal 20 isdepressed, the piston 17 forces iiuid from the master cylinder betweenthe pistons 52 and 53 in the cylinder 26 and pistons 74 and 75 in thecylinder 27, thus causing outward movement ot the latter pistons whichforce the iluid in advance of these pistons .to the cylinders l45 toveiiect operation of the `pistons 44 and thus expand the brake devices41. In the embodiment described the entire lsystem is equalizedthroughout and equalized pressure may be' transmitted to the brakedevices `associated with all four wheels of the vehicle, and by reasonof the segregation of thebody of fluid contained within the mastercylinder 10," such body of uid can never be diminished by breakage orleakage in any ofthe ilexible connections 40, 47, 50, and l;consequently no iluid can be st Afrom the master cylinder .10 by reason0i .such breakageorieakage. l

the remaining three brake 'devices Should one oi' the exibleconnections, flexible connection 40 for instance, leak, and only somelluid escape by reason oi leakage, additional iluid will be supplied bythe reservoir 63 to compensate for such leakage as may occur, andconsequently prevent any impairment of the braking emciency o! thesystem. Should one of the ilexible conduits, again 40, for example,entirely break, so as to permit all oi' the uid in the conduit andadjacent end of the cylinder 26 to escape, the piston 53, when pressureis applied to .the pedal 20, will move to its extreme outer position,and will be returned by the spring 62, in the same manner as though thenuid had not been lost, and without aiecting equalization on In otherwords only one of the brake devices will be cut out and only thatportion of fluid directly acting with rei'erence to said braking devicelost. Should the ilexible connection 50, as well as the flexibleconnection 40, break, the piston 52 will move to its extreme outerlimit, and only the portion of fluid directly associated therewith willbe lost, this without aiecting the equalized operation of the brakedevices of the remaining two wheels of the vehicle, the reserve in thereservoir 22 compensating for the additional movementof the piston 52.Should still another conduit, 47 for example, also break, there stillwill be one brake device operative, as will be understood. During any orall of the breakage which might occur as heretofore discussed, none ofthe major portion of the uid contained within the reservoir 22, mastercylinder 10, and between the pistons 52 and 53 oi' the cylinder 26 andpiston 74 and75 of the cylinder 27 will be l lost.

Under the circumstances entire safety is provided, absolute equalizationo! pressure being obtained upon the brake devices so long as two or moreare in operation, leakage in individual conduits may readily be takencare of, and breakage in a conduitor conduits results in the loss of asmall localized body of iluid directly associated with the conduit inwhich breakage occurs.

Thus it'will be apparent to those skilled in the art that I haveaccomplished at least the principal object ofmy invention, and it willbe appreciated that the invention is susceptible to uses and hasadvantages other than those herein pointed out, and may be variouslychanged and modiiled without departing from the spirit of the invention;accordingly those skilled in the art will realize that the embodimentherein disclosed is illustrative only and that the invention is notlimited thereto.

I claim: e

1. A hydraulic brake system, comprising: a casting havinga maincylinder, and a ,pair of auxiliary cylinders arranged side by side andder; brake operating devices; a iirst body oi' iiuid being normallyconned between said main piston and one side o! each o! said auxiliarypistons,

and projecting beyond one end of said main cylinder, said main cylinderhaving a wall con tinuous with said common wall and projecting beyondone end of said auxiliary cylinder; a

main piston reciprocally mounted in said main cylinder; a lpair ofauxiliary pistons disposed within said auxiliary cylinder, spaced fromeach other and coniined to reciprocation within a portion only thereof;a duct in said common wall, communicating with said main cylinder andwith the space between the auxiliary pistons in said one auxiliarycylinder; brake operating devices, each communicating with opposite endsof said auxiliary cylinders; a rst body of iluid being normally conilnedbetween said main piston and one side of each of said auxiliary pistons,and independent second bodies of iluid being normally confined betweensaid brake operating devices and the opposite sides of said auxiliarypistons; said casting having a pair of reservoirs one arranged at eachend of said auxiliary cylinder, and having a common wall therebetween;and a duct for each of said reservoirs. disposed in the latter commonwall, each duct communicating with one of said reservoirs and itsassociated second body of iluid, whereby said reservoirs automaticallyoperate to replenish deilciency of fluid in said second bodies of iluid;and braking action of said main piston transmits fluid pressure to saidbrake operating devices to eitect braking of the same. l

3. A hydraulic brake system, comprising: a main cylinder containing amain piston: an auxiliary cylinder having-a port intermediate its endscommunicating .with said main cylinder; a pair o! auxiliary pistonsdisposed in saidauxiliary cylinder, and spaced from each other onopposite sides ofsaid port; aiirstbodyofiiuidbeing normally confinedbetween said main piston and one side of said auxiliary pistons; brakeoperating devices each communicating with the ends of said auxiliarycylinder; a pair of second bodies of i'luid being normally coniinedbetween the other side of 'said auxiliary pistons and said associatedbrake operating devices; said auxiliary pistons preventing fluidcommunication therepast, ting saidfnrst body or mud from indd pressureto saidtwo auxiliary pistons,

ends communicating with said main cylinder; a

pair of auxiliary pistons disposed in said auxiliary cylinder. andspaced from each other on opposite sides of said port: a iirst body offluid being normally confined between said main piston and one side ofsaid auxiliary pistons; brake 4operating devices each communicating withthel ends of said auxiliary cylinder; a pair of second bodies of iluidbeing normallyconilned between the other side of said auxiliary pistonsand said associated brake operating devices; said auxiliary' pistonspreventing fluid communication therepast, ,segregating said first bodyofiluid from said second bodies of iiuid; an auxiliary reservoir foreach of said second bodies of fluid, mounted on said auxiliary cylinderat the ends thereof, and automatically operable to replenish deficiencyof iiuid in said second .bodies of fluid; a by-pass communicable withsaid iirst body and said second bodies of fluid; a valve in said bypassfor each of said second bodies of iluid, each valve subjected only toiluid pressure in its associated second body of iluid; a-valve in saidbypass for said rst body of iluid, subjected only to fluid pressure insaid rst body of iluid; said valves being operable to establish iluidcommunication from said ilrst body of iluid to any one of said secondbodies of iiuid to thereby replenish deficiency of fluid in any one ofsaid auxiliary'reservoirs and any one of said second bodies of iiuid;and braking action of said main piston transmits nuid pressure to saidtwo auxiliary pistons, spreading apart said two auxiliary pistons, eachof the latter transmitting iluid pressure to its associated brakeoperating devices to effect braking of the same.

5. A hydraulic brake system, comprising: a casting having a maincylinder, and a pair of auxiliary cylinders arranged side by side andhaving a common wall therebetween; a pair of auxiliary pistons disposedwithin each of said auxiliary cylinders, spaced from each other andconilned to reciprocation within a portion only thereof; a duct in thewall common to said auxiliary cylinders, communicating with saidauxiliary cylinders in the space between said auxiliary pistons; a ductin the wall of one of said auxiliary cylinders, communicating with saidmain cylinder and with the space between the auxiliary pistons in saidvone auxiliary cylinder; brake operating devices communicating with saidauxiliary cylinders; a first body of fluid being normally coniinedbetween said main piston and one side of each of said auxiliary pistons,and independent second bodies of iiuid being normally confined between.said brake operating devices and the opposite sides of said auxiliarypistons; said casting havng a plurality of reservoirs, each arrangedside by side with each of said auxiliary cylinders adjacent the oppositeends thereof, and having a common wall therebetween; and a duct for eachof said reservoirs, disposed in the latter common walls, each ductcommunicating with one of said reservoirs and with its associated secondbody of uid.- whereby said reservoirs automatically opcrate to replenishdencieney of fluid in said secondbodiesofiiuid; aby-passdrilledoutctsaidcasting, longitudinally of each of said auxiliary cylinders.communicable with said ilrst body and said second bodies ot duid; avalve in said bypass for each of said second bodies o! uid, each v alvesubjected only to iluid pressure in its associated second body of fluid;a valve in said bypass for said first body of iiuid, subjected only toduid pressure in said first body of iluid; said valves being operable toestablish fluid communication i'rom saidfirst body of uid to any one ofsaid second bodies o1 fluid, to thereby replenish deficiency-'of duid inany one of said auxiliary reservoland any one of said second bodies otfluid; Yand braking action of said main piston transmits uid pressure tosadbrake operating devices to eiect braking of the-same..

6. In a hydraulic brake system, a main cylinder containing a mainpiston; van'auxiliarylcylinder of constant diameter throughout itslength, and having a port intermediate its ends communicating with saidmain cylinder; a pair of auxiliary pistons disposed in saidk auxiliarycylinder, and spaced from each other, and each confined to reciprocationwithin a portion only thereof; a first body of fluid being normallyconfined between said main piston and one side of said auxiliarypistons; a stop for each of said auxiliary pistons disposeddiametrically in said auxiliary cylinder adjacent to said port therein,each stop operating to prevent-its associated auxiliary Diston fromobstructing said port; and brake operating devices, each communicatingwith said auxiliary cylinder adjacent the opposite sides oi' saidauxiliary pistons; a second .body of uid being normally confined betweensaid auxiliary pistons and said brake operatingdevices:4 said auxiliarypistons preventing fluid communication therepast, segregating said firstand second bodies ot fluid; whereby braking action of said main pistontransmits fluid pressure to said brake operating devices to eiTectbraking of the same.

7. In a hydraulic vbrake system, a main cylinder containing a mainpiston; an auxiliary cylinder of constant diameter'throughout itslength, and having a port intermediate yits ends commumcating with saidmain cylinder, said auxiliary cylinder having a pair oi' diametricallydisposed notches at each side of said port; a pair of auxiliary pistonsdisposed in said auxiliary cylinder, and spaced from each other, andeach conned to reciprocation within a portion only thereof; a rst bodyo! uid being normally conned between said main piston and one side ofsaid auxiliary pistons; a resilient stop for each of said auxiliarypistons initially sprung into position in the notches in said auxiliarycylinder adjacent to said port therein, each resilient stop operating toprevent its associated auxiliary piston from obstructing said, port; andbrake operating devices, each communicating with said auxiliary cylinderadjacent the opposite sides ot said auxiliary pistons; a second body ofuid being normally confined between said auxiliary pistons and saidbrake operating devices, said auxiliary pistons preventing iluidcommunication therepast, segregating said rst and second bodies offluid; whereby braking action of said main piston transmits iuidpressure to said brake operating devices to eilect braking of the same.

HENRY ci;V RHODES. u

